1. Field of the Invention
The present invention relates to methylolamino curing agents.
2. Description of the Art Practices
Melamine was first developed by Von Liebig in 1834 and since that time various alkoxy derivatives of melamine have been utilized in the coating art by the transetherification with various polyhydric compounds.
Among some of the art describing the curing of alkoxymethylaminotriazenes (melamineformaldehyde resins) are U.S. Pat. No. 3,449,467 issued to Wynstra on June 10, 1969 and U.S. Pat. No. 3,668,276 issued on June 6, 1972 to Riemhofer et al. The aforementioned patents disclose hydroxy polyesters of moderately high molecular weight aminoplasts. U.S. Pat. No. 3,852,375 issued Dec. 3, 1974 to Biethan et al and 3,920,595 issued Nov. 18, 1975 to Anderson et al and 3,959,201 issued May 25, 1976 to Chang each disclose high solids coating compositions comprising blends of hydroxy polyesters of moderately low molecular weight and aminoplast curing agents.
Furthermore, U.S. Pat. No. 3,980,732 issued Sept. 14, 1976 to Isaksen et al and U.S. Pat. No. 3,994,851 issued Nov. 30, 1976 to Chang also disclose the use of material which relates to the present invention. U.S. Pat. No. 4,119,762 issued to Anderson et al on Oct. 10, 1978 also discloses the use of low molecular weight polyols as curing agents for melamine type resins. An overview of the use of melamine type materials as coating agents is found in "Organic Coating Technology", Volume 1 by Henry Fleming Payne, published by John Wiley & Sons, Inc., copyright 1954, fourth printing, pages 333,350; a similar disclosure of melamine resins is found at Chapter 46 (Petropoulos et al) of a book entitled "Applied Polymer Science", published by the American Chemical Society, 1975.
Melamine resins are also discussed in a reprint of an article entitled "A New Approach To Formulation of WaterBorne Coatings" found in the August 1977 issue of the Journal of Coatings Technology, Volume 49; Number 631; Pages 4659. Similarly an article by Golownia entitled "High Solids Coatings For Appliances" found in the publication High Solids Coatings, June 1978, Pages 214. The performance expectation needs of the appliance coating industry are described.
Melaminepolyol coating compositions are disclosed in British Pat. No. 1,308,697 issued Feb. 28, 1973. Moreover, U.S. Pat. No. 3,741,935 to Dowbenko issued June 26, 1973 describes high solids thermosetting coating compositions containing melamine materials. In German OLS 2,326,598 issued Dec. 6, 1973 in the name of Henshawl et al melamine curing agents are disclosed.
Chang in German OLS No. 2,447,812 issued Apr. 17, 1975 describes various caprolactone adducts of melamine derivatives. In Japanese Pat. No. 76 95,493 issued Aug. 21, 1976 polyol condensed melamine resins are described by Harada et al. Resin coating compositions for plastic products are also described in another Japanese Pat. No. 76 97,634 also to Harada et al. Polycaprolactone polyol derivatives of melamine products and low molecular weight polyols are described in U.S. Pat. No. 4,101,603 issued July 18, 1978 to Smith et al.
U.S. Pat. No. 4,113,793 to Sekmakas issued Sept. 12, 1978 describes high solids rapid curing thermosetting melamine derivative products. The present invention is also concerned with a known diol as reported in U.S. Pat. No. 3,243,414 issued Mar. 29, 1966 to DeWitt et al. In addition, the higher polyols are described in a United States Patent application to Rogier, but which does not suggest the use of such materials as melamine curing agents.
The term methylolamino compound denotes the product of an amino compound and an aldehyde (usually formaldehyde giving rise to the methyl term) which is useful in forming resins. Ordinarily these materials are etherified or partially etherified to obtain an alkoxy derivative of methylolamino compound which is then used as the resin and these terms are used interchangeably.
Thus, embraced herein are materials shown in the formulas below as the polyfunctional amino compound EQU (R'HN).sub.n --R--NHR"
where n is 1 or greater, R' and R" are hydrogen or other groups including cyclo forming carbons and where R is a carbon containing backbone.
Throughout the specification and claims percentages and ratios are by weight and temperatures are in degrees of Celsius unless otherwise indicated. The foregoing references to the extent applicable are herein incorporated by reference.